Method for making metallic cover

ABSTRACT

An exemplary method for making a metallic cover includes the following steps: providing a raw metallic block ( 20 ); rolling a pressing machine ( 30 ) on the metallic block to form a preformed body ( 40 ); and machining the preformed body  40  in a high precision machining process to yield a metallic cover ( 60 ). The thickness of a predetermined portion of the metallic cover is different from that of other portions of the metallic cover.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to methods for making metallic covers, and more particularly to a method for making a metallic cover used for a portable electronic device.

2. Discussion of the Related Art

Nowadays, portable electronic devices such as mobile phones and personal digital assistants (PDAs) are in widespread use around the world. There is more and more demand for higher quality and functionality of these portable electronic devices. Portable electronic devices have all kinds of functions such as storage, keeping a record of events, game functions, wireless application protocol (WAP) functions, sending information, and so on. However, aesthetics is also important for a portable electronic device, thus the cover of the portable electronic device should be made of a good material, and has a high manufacturing precision. Covers of portable electronic devices are generally made of two kinds of materials (plastic and metallic). Generally, a metallic cover has a nicer appearance and a better surface feeling than a plastic cover, thus metallic covers for portable electronic device are now becoming more and more popular.

The thickness of most covers of portable electronic devices are unequal, for example, the thickness of a predetermined portion of a cover of a portable electronic device is different from that of other portions of the cover. This unequal-thickness covers are easy to be made of plastic material by injection molds, but the metallic unequal-thickness covers are hard to be manufactured by injection molds.

At present, metallic unequal-thickness covers are generally manufactured by milling machines. A first typical method for making a metallic cover will now be described. A raw metallic block is provided. The raw metallic block has to go through several milling processes so as to get a preformed body. The preformed body is made into a metallic cover by a process of finish machining. The above method for making metallic unequal-thickness covers takes a great deal of time, for example, it needs more than ten hours for a process to make a metallic cover of a mobile phone. Because the metallic cover goes through several milling processes the efficiency of the described method is low and a lot of metallic materials removed from the raw metallic block are wasted, thereby increasing the cost of the metallic covers. Another typical method for making a metallic cover includes the following steps: providing a metallic sheet; punching the metallic sheet to yield a preformed body; and milling the preformed body to yield a metallic cover. However, it still takes several hours to make the metallic cover. In addition, the hardness of the covers made by the above two methods is not improved in the manufacturing process, thereby the abrasive resistance of the cover is not high enough.

Therefore, a new method having high efficiency for making a metallic cover is desired.

SUMMARY

A method for making a metallic cover includes the following steps: providing a raw metallic block; rolling a pressing machine on the metallic block to form a preformed body; and machining the preformed body in a high precision machining process to yield a metallic cover. The thickness of a predetermined portion of he metallic cover is different from that of other portions of the metallic cover.

Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily drawn to measuring scale, the emphasis instead being placed upon clearly illustrating the principles of the method for making a metallic cover. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic, isometric view of a raw metallic block for making a metallic cover according to the present invention.

FIG. 2 is a schematic, cross-sectional view of a pressing machine in a first state of a method for making a metallic cover according to the present invention.

FIG. 3 is similar to FIG. 2, but showing a second state of the method.

FIG. 4 is a schematic, isometric view of a perform body made by the method according to the present invention.

FIG. 5 is a schematic, isometric view of a metallic cover made by the method according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made to the drawings to describe, in detail, preferred embodiments of the present method for making metallic covers. The method can be used for making metallic covers of portable electronic devices such as mobile phones and personal digital assistants (PDAs), and especially for making metallic covers which have an unequal-thickness, for example, the thickness of a predetermined portion (in the preferred embodiment, the predetermined portion is a central portion) of a cover of a portable electronic device is thinner than that of other portions of the cover.

Referring to FIGS. 1 through 5, the method for making a metallic cover includes the following steps: providing a raw metallic block 20; rolling a pressing machine 30 on the metallic block 20 to form a preformed body 40; and machining the preformed body 40 in a high precision machining process to yield a metallic cover.

Referring to FIG. 1 again, the raw metallic block 20 is extracted (in preferred embodiment is cut out) from a metallic sheet and the raw metallic block 20 has a size and a shape corresponding to the metallic cover 60 (see FIG. 5) of a portable electronic device (not shown). In this embodiment, the metallic block 20 is made of aluminum alloy. It can be understood that the metallic block 20 can also be made of other metallic materials, for example, magnesium alloy.

Referring to FIGS. 2 through 4, the pressing machine 30 includes a rotatable press mold 301, and a molding platform 302. The rotatable press mold 301 can be driven by an actuator (not shown) to roll at certain angles from a first predetermined direction to a second predetermined direction. When the rotatable press mold 301 is rolled to an utmost position, a central axis of the rotatable press mold 301 relative to a surface normal to a mounting surface 3021 of the molding platform 302 defines an utmost roll angle β. The utmost roll angle β is designed according to a desired structure of the metallic cover 60 The rotatable press mold 301 includes a molding end 3010 having a molding surface 3011 facing the molding platform 302. The shape of the mold surface 3011 is configured corresponding to the desired structure of the metallic cover 60. In the preferred embodiment, the mold surface 3011 is a spherical surface. The thickness of the mold end 3010 of the rotatable press mold 301 deceases gradually from a central portion of the mold end 3010 to a peripheral portion of the mold end 3010. The molding platform 302 includes a mounting surface 3021 for receiving the metallic block 20.

In use, the metallic block 20 is disposed on the mounting surface 3021. The rotatable press mold 301 is driven to press on the metallic block 20 and further to roll at certain angles from the first predetermined direction to the second predetermined direction. Due to the mold surface 3011 of the mold end 3010, when the metallic block 20 is pressed by the rotatable press mold 301, particles (composition and substance) of the metallic block 20 will be displaced (moved, pushed, and shifted) away from an area affected by the rotatable press mold 301. The area affected by the rotatable press mold 301 would be concave and taking a form according to the mold surface and the rolled direction. As a result, the thickness of the predetermined portion of the metallic block 20 would be smaller than the thickness of other portions of the metallic block 20. During a press process as mentioned above, the particles of the metallic block would be more compress, thus yielding a cover that is more hardened and sturdy. The metallic block 20 is made into a preformed body 40 by the mold surface 3011 of the rotatable press mold 301. The preformed body 40 has a size and a shape substantially the same as the metallic cover 60 to be made.

In alternative embodiments, the molding platform 302 defines a through hole 3022 for receiving a push device 303 of the pressing machine 30. The push device 303 is configured for releasing the preformed body 40 from the molding platform 302 of the pressing machine 30 by pushing the preformed body 40 out of the molding platform 302. A latching stub 201 extends from a central portion of the metallic block 20 and is configured for engaging in the though hole 3022 so as to secure the metallic block 20 on the molding platform 302. The latching stub 201 is formed on the metallic block 20 but before the metallic block 20 is pressed by the pressing machine 30. A cross-section of the latching stub 201 corresponds to the though hole 3022. The cross-section of the latching stub 201 is non-circular, for example, the cross-section of the latching stub 201 can be rectangular. In this embodiment, the push device 303 is a shaft and a cross-section of the shaft is the same as the cross-section of the latching stub 201.

Referring to FIG. 5, the preformed body 40 (of FIG. 4) is then further machined in a high precision machining process, thereby yielding the metallic cover 60. In this embodiment, the preformed body 40 is machined in a high precision milling machine, (for example, a high precision milling process). Since the preformed body 40 formed by the pressing machine 30 has a size and a shape substantially the same as the metallic cover 60, the time used for the high precision machining process is considerably decreased Furthermore, because the metallic material of the metallic cover 60 is pressed by the pressing machine 30, mechanical properties and performances of the metallic cover 60 are also improved, for example, the hardness of the metallic cover 60 is improved, and thus, also increasing an abrasive resistance of the metallic cover 60.

In the process of forming the preformed body 40, because the metallic block 20 is pressed by the pressing machine 30 to form the preformed body 40, thus no metallic material is removed from the metallic block 20. In the process of machining the preformed body 40, because the preformed body 40, formed by the pressing machine 30, has a size and a shape substantially the same as the metallic cover 60, only a small quantity of metallic materials is removed from the preformed body 40 and the machining efficiency is greatly improved. In the method for making the metallic cover, because the pressing machine 30 is much smaller and safer than a punch machine, and no oscillation is caused, thus the pressing machine 30 has a long serve life.

It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A method for making a metallic cover, comprising: providing a raw metallic block; rolling a pressing machine on the metallic block to form a preformed body; and machining the preformed body in a high precision machining process to yield a metallic cover, wherein the thickness of a predetermined portion of the metallic cover is different from that of other portions of the metallic cover.
 2. The method for making a metallic cover as claimed in claim 1, wherein the metallic cover is made of aluminum alloy.
 3. The method for making a metallic cover as claimed in claim 1, wherein the preformed body has a shape and size substantially the same as those of the metallic cover.
 4. The method for making a metallic cover as claimed in claim 1, wherein the pressing machine includes a rotatable press mold and a molding platform, the raw metallic block is disposed on the molding platform, and the rotatable press mold is driven to press on the metallic block and further to roll at certain angles on the raw metallic block from a first predetermined direction to a second predetermined direction.
 5. The method for making a metallic cover as claimed in claim 4, wherein the rotatable press mold includes a mold end having a mold surface facing the molding platform, and the shape of the mold surface is configured corresponding to the desired structure of the metallic cover.
 6. The method for making a metallic cover as claimed in claim 5, wherein the predetermined portion is a central portion of the cover.
 7. The method for making a metallic cover as claimed in claim 6, wherein the thickness of the mold end of the rotatable press mold deceases gradually from a central portion of the mold end to a peripheral portion of the mold end.
 8. The method for making a metallic cover as claimed in claim 7, wherein the molding platform includes a mounting surface for mounting the metallic block and the mold surface is a spherical surface.
 9. The method for making a metallic cover as claimed in claim 8, wherein the molding platform defines a though hole for receiving a push device, and the push device is configured for releasing the preformed body from the molding platform of the pressing machine by pushing the preformed body out of the molding platform.
 10. The method for making a metallic cover as claimed in claim 9, wherein the metallic block further comprises a latching stub extending from a central portion thereof, and the latching stub is configured for engaging in the though hole so as to secure the metallic block on the molding platform.
 11. The method for making a metallic cover as claimed in claim 10, wherein the latching stub comprises a non-circular cross-section corresponding to the though hole.
 12. The method for making a metallic cover as claimed in claim 1, wherein the push device is a shaft, and a cross-section of the shaft is the same as the cross-section of the latching stub.
 13. The method for making a metallic cover as claimed in claim 1, the high precision machining process is a high precision milling process.
 14. A method for making a metallic cover, comprising: providing a raw metallic block; rolling a pressing machine on the metallic block to form a preformed body; and machining the preformed body in a high precision milling process to yield a metallic cover, wherein the thickness of a middle portion of the metallic cover is thinner than that of other portions of the metallic cover.
 15. The method for making a metallic cover as claimed in claim 14, wherein the metallic cover is made of aluminum alloy.
 16. The method for making a metallic cover as claimed in claim 15, wherein the pressing machine includes a rotatable press mold and a molding platform, the raw metallic block is disposed on the molding platform, and the rotatable press mold is driven to press on the metallic block and further to roll at certain angles on the raw metallic block from a first predetermined direction to a second predetermined direction.
 17. The method for making a metallic cover as claimed in claim 16, wherein the rotatable press mold includes a mold end having a mold surface facing the molding platform, and the shape of the mold surface is configured corresponding to the desired structure of the metallic cover.
 18. The method for making a metallic cover as claimed in claim 17, wherein the thickness of the mold end of the rotatable press mold deceases gradually from a central portion of the mold end to a peripheral portion of the mold end.
 19. The method for making a metallic cover as claimed in claim 18, wherein the molding platform includes a mounting surface for mounting the metallic block and the mold surface is a spherical surface.
 20. The method for making a metallic cover as claimed in claim 18, wherein the molding platform defines a though hole for receiving a push device, the push device is configured for releasing the preformed body from the molding platform of the pressing machine by pushing the preformed body out of the molding platform, the metallic block further comprises a latching stub extending from a central portion thereof, and the latching stub is configured for engaging in the though hole so as to secure the metallic block on the molding platform. 